scholarly journals Outbreak of Brown Spot of Tobacco Caused by Alternaria alternata in Connecticut and Massachusetts

Plant Disease ◽  
2001 ◽  
Vol 85 (2) ◽  
pp. 230-230 ◽  
Author(s):  
J. A. LaMondia
Keyword(s):  
New England ◽  
Alternaria Alternata ◽  
Potato Dextrose Agar ◽  
Brown Spot ◽  
Leaf Spot Disease ◽  
Connecticut River ◽  
Surface Sterilization ◽  
Nicotiana Tabacum L ◽  
Plastic Bag ◽  
Natural Leaf

In early August 2000, a leaf spot disease of broadleaf tobacco (Nicotiana tabacum L.) was widespread and severe in Connecticut and Massachusetts. The spots were roughly circular, with necrotic centers and concentric rings and often surrounded by a yellow halo. Spots ranged in size from small fleck symptoms (approximately 1 mm) to large lesions 1 to 3 cm in diameter. The putative tobacco brown spot pathogen, Alternaria alternata (Fr.:Fr.) Keissl., was isolated on potato-dextrose agar from symptomatic tissues after surface-sterilization for 30 s in 0.525% NaOCl. Brown conidia were produced in culture, often in chains. Conidia were variable in size, but tapered to a lighter colored short beak that was usually less than one quarter the length of the conidia (1). Healthy, detached broadleaf leaves (the first fully expanded leaves) were inoculated with 25 drops (45:1 each) of water alone or water containing 5.0 × 104 conidia combined from ten cultures (four leaves for each treatment). Drops were placed in the area between veins and allowed to air-dry for 3 h. Leaves were then misted and placed in a plastic bag in a growth chamber maintained at 24°C with 8 h light per day. Brown spot symptoms developed in 25% of the inoculated spots but not in areas of water controls after 11 days. Symptomatic tissue was surface-sterilized and A. alternata was consistently reisolated on potato-dextrose agar. Brown spot commonly occurs in the Connecticut River Valley on senescent leaves near the soil; however, in August 2000, symptoms were present on leaves of all ages. The greatly increased incidence and severity of brown spot were likely due to unusually wet conditions during the 2000 cropping season (2). In Windsor, CT, an average of 3 days per week of rain was recorded throughout the growing season. Brown spot symptoms render broadleaf tobacco leaves unsuitable for use as a natural leaf cigar wrapper and result in a complete loss of value. Data released by the New England National Agricultural Statistics Service on 1 September 2000 indicated that broadleaf tobacco losses in Connecticut and Massachusetts were at least 75 and 89% of the total acreage, respectively. References: (1) G. B. Lucas. Tob. Sci. 15:37,1971. (2) J. R. Stavely and C. E. Main. Phytopathology 60:1591, 1970.

scholarly journals Characterization of Alternaria alternata causal agent of brown spot in Citrus spp

2017 ◽  
Vol 1 (2) ◽  
pp. 45
Author(s):  
Aline Vanessa Sauer ◽  
Hugo José Tozze Júnior ◽  
Marcel Bellato Spósito ◽  
Eduardo Feichtenberger Feichtenberger ◽  
Nelson Barros Colauto ◽  
...  
Keyword(s):  
Alternaria Alternata ◽  
Genetic Similarity ◽  
Mycelial Growth ◽  
Potato Dextrose Agar ◽  
Brown Spot ◽  
Growth Speed ◽  
Phenological Stages ◽  
Rough Lemon ◽  
Citrus Spp

The purpose of this study was to characterize culturally, enzymatically and pathogenically Alternaria alternata isolates obtained of tangerine/tangor (TP) and rough lemon (RLP). Significant differences were observed regarding mycelial growth speed and sporulation of isolates when cultivated in starch-agar (SA), potato-dextrose-agar (PDA) and tomato juice agar (V8) media. SA and PDA media promoted better mycelial growth and sporulation, respectively. Eight genetic similarity groups were defined through isoenzymatic characterization but without correlation between isolates and host or site of origin. All isolates produced amylase, cellulase, polygalacturonase and pectynase; however, no lipolytic or proteolytic activity was observed. Disease incubation period varied between 24 to 48 h for all isolates in all phenological stages of the inoculated fruit. Symptomatic fruit incidence in most tangerine and tangor isolates was higher in stage F3 compared to stages F4 and F5. Alternaria alternata have the ability to perform hyphal anastomosis indicating that this can be a mechanism used by the fungus to increase genetic variability.

scholarly journals First Report of Alternaria alternata as a Dieback Pathogen of Kiwifruit

Plant Disease ◽  
2000 ◽  
Vol 84 (3) ◽  
pp. 371-371 ◽  
Author(s):  
P. C. Tsahouridou ◽  
C. C. Thanassoulopoulos
Keyword(s):  
Alternaria Alternata ◽  
Morphological Characteristics ◽  
Potato Dextrose Agar ◽  
Conidial Suspension ◽  
Actinidia Chinensis ◽  
Northern Greece ◽  
Disease Symptoms ◽  
First Report ◽  
Surface Sterilization ◽  
Pathogenicity Tests

During a survey of diseases on kiwifruit (Actinidia chinensis) cv. Hayward during spring 1998 in Northern Greece, leaves of kiwifruit trees were found covered with small, necrotic brown spots. Intense spotting was associated with defoliation. Furthermore, small, sunken, dark brown cankers appeared a few centimeters below the twig tip, and twigs died distal to the canker a few days later, while the twig remained healthy below the canker, often producing a new shoot below the canker. Isolations from symptomatic leaves and internal tissues of twigs on potato dextrose agar (PDA), after surface-sterilization with 0.5% NaOCl and 90% alcohol, respectively, consistently yielded a fungus that, based on conidial morphological characteristics, was identified as Alternaria alternata (Nees:Fr.) Keissl. (2). Pathogenicity tests were performed on 3-year-old kiwi plants. Tests on twigs were conducted by inoculating 35 twigs with 5-mm disks from 7-day-old cultures on PDA at 25°C. Each twig was inoculated with three disks. Tests on leaves were conducted by spraying a conidial suspension (5 × 106 conidia per ml) of the cultures on leaves. Plants were kept in a glasshouse at 22 to 25°C. Symptoms, identical to those observed in the field, developed on leaves and twigs 6 and 18 days, respectively, after inoculation. All inoculated leaves exhibited symptoms of the disease, whereas more than 95% of inoculated twigs exhibited disease symptoms. A. alternata was consistently reisolated from inoculated tissues. A. alternata is widely known to be a leaf spot pathogen of kiwifruit (1). This is the first report of A. alternata causing twig dieback. References: (1) L. Corazza and L. Luongo. Plant Dis. 83:487, 1999. (2) E. G. Simmons. Mycotaxon 37:79, 1990.

The expression of a baculovirus-derived chitinase gene increased resistance of tobacco cultivars to brown spot (Alternaria alternata)

2000 ◽  
Vol 136 (1) ◽  
pp. 1-8 ◽  
Author(s):  
J SHI ◽  
C J THOMAS ◽  
L A KING ◽  
C R HAWES ◽  
R D POSSEE ◽  
...  
Keyword(s):  
Alternaria Alternata ◽  
Chitinase Gene ◽  
Brown Spot

scholarly journals First Report of Alternaria Leaf Spot of Almond Caused by Species in the Alternaria alternata Complex in California

Plant Disease ◽  
2001 ◽  
Vol 85 (5) ◽  
pp. 558-558 ◽  
Author(s):  
B. L. Teviotdale ◽  
M. Viveros ◽  
B. Pryor ◽  
J. E. Adaskaveg
Keyword(s):  
Alternaria Alternata ◽  
Leaf Spot ◽  
Disease Incidence ◽  
Prunus Dulcis ◽  
Leaf Spot Disease ◽  
Yield Losses ◽  
Mature Leaves ◽  
Branching Chains ◽  
Paper Towels ◽  
Industry Conference

A new leaf spot disease of almond (Prunus dulcis [Mill.] D. Webb) was observed in California in the late 1980s and was first associated with severe defoliation in the mid-1990s (1). Orchards in areas with frequent summer dews, high humidity, and little air movement sustained severe defoliation, resulting in yield losses often exceeding 50%. Symptoms occur only on leaf blades in late spring and summer. Lesions develop as small, circular, tan spots 1 to 3 mm in diameter that may enlarge to 5 to 20 mm in size. Semicircular lesions frequently develop along the leaf margins and tips. The centers of mature lesions become black with fungal sporulation. The fungi isolated from the margins of sporulating and non-sporulating lesions were identified as three species in the Alternaria alternata complex: A. alternata, A. arborescens, and A. tenuissima (2,3). Cultures grown in the dark on potato dextrose (PDA) or potato-carrot agar are grayish white to olivacious green in the former two species and dark gray and wooly in the latter species. On 5% PDA, cultures of all three species produced catenulate dictyospores that were granular to punctate (-verrucose), pale yellowish to brown or black, and had visible apical and basal pores. Conidial morphology depended on chain position; apical conidia ranged from ovoid to ellipsoid, whereas basal conidia were elliptical to obclavate. Average conidial dimensions of A. alternata and A. arborescens ranged from 20 to 28 × 8 to 10 μm. Conidia of A. alternata were produced in acropetal succession in branching chains on single, short suberect conidiophores. A. arborescens produced conidia similarly but mostly in dichotomously branching chains on short to long conidiophores. Average conidial dimensions of A. tenuissima ranged from 20 to 34 × 8 to 12 μm and they were produced in simple chains with one or two branches forming occasionally. In preliminary studies, the optimum temperature for mycelial growth on PDA for all three species ranged from 24 to 28°C. Fifty mature leaves on each of four 7- or 8-year-old almond cv. Butte trees were inoculated at 2- to 3-week intervals from mid-spring through summer in 1999 and 2000. Leaves were sprayed with aqueous suspensions containing 105 conidia per milliliter for one isolate each of A. alternata and A. arborescens and two isolates of A. tenuissima or with sterile distilled water. The shoots were covered for 72 h with plastic-lined brown paper bags containing wet paper towels. Leaves were examined for infection after 7 and 14 days. All isolates were pathogenic and produced non-sporulating lesions similar to those observed in natural infections. No symptoms were observed on noninoculated control plants. Disease incidence was low (<15%) until late June 1999 and July 2000. Inoculations in summer produced increasingly more infections, reaching incidences of 40 to 52% in September 1999 and 18 to 80% in August 2000. References: (1) J. E. Adaskaveg. 1994. Pages 5–7 in Proceedings of the 22nd Annual Almond Industry Conference. 1994. (2) J. Rotem. 1994. The genus Alternaria. Biology, Epidemiology, and Pathogenicity. APS Press, St. Paul, MN. (3) E. G. Simmons. Mycotaxon 70:325–369, 1999.

Jonathan Edwards's Change of Position On Stoddardeanism

1981 ◽  
Vol 74 (1) ◽  
pp. 79-99
Author(s):  
John F. Jamieson
Keyword(s):  
New England ◽  
River Valley ◽  
Jonathan Edwards ◽  
Historical Knowledge ◽  
Connecticut River ◽  
Connecticut River Valley

When Jonathan Edwards was installed as assistant to his grandfather Solomon Stoddard at Northampton in 1727, he not only assumed the major pastoral responsibility for the largest congregation in western Massachusetts, but he also became coadministrator of the “lax” mode of admission to the sacraments that had prevailed at Northampton and throughout the Connecticut River Valley for some thirty years. This system granted both baptism and communion to all persons of age who had historical knowledge of the gospel and were of a “non-scandalous” life, on the grounds that all divinely established ordinances were capable of “begetting” faith. Although Stoddard did not originate the “lax” system, the practice was generally referred to as “Stoddardeanism” because from the time of his celebrated dispute with Increase Mather in 1700 (the so-called “Stoddardean controversy”) Stoddard had been its most systematic, persistent, and influential proponent in New England.

scholarly journals Brown spot of tangerine hybrid cultivars Minneola, Page and Fortune caused by Alternaria alternata in Iran

2006 ◽  
Vol 55 (4) ◽  
pp. 578-578 ◽  
Author(s):  
M. Golmohammadi ◽  
M. Andrew ◽  
T. L. Peever ◽  
N. A. Peres ◽  
L. W. Timmer
Keyword(s):  
Alternaria Alternata ◽  
Brown Spot

A New Leaf Spot Disease of Calotropis gigantean Caused by Alternaria alternata in Rajasthan, India

2009 ◽  
Vol 10 (1) ◽  
pp. 45
Author(s):  
Satish K. Sain ◽  
H. N. Gour ◽  
P. Sharma ◽  
P. N. Chowdhry
Keyword(s):  
Alternaria Alternata ◽  
Leaf Spot ◽  
First Record ◽  
Leaf Spot Disease ◽  
Koch’S Postulates ◽  
Calotropis Gigantea ◽  
Spot Disease ◽  
Koch's Postulates

Madar (Calotropis gigantea) is a medicinally important wild shrub native to India. The seed floss is used for furniture stuffing and the bark for nets and twine. In early 2005, we observed a leaf spot epidemic of madar growing on wasteland sites near the Sikar district of Rajasthan, India. Koch's Postulates were completed. This is the first record of the disease from the Sikar district of the Rajasthan state of India. Accepted for publication 6 February 2009. Published 31 March 2009.

scholarly journals Leaf Spot Disease Caused by Alternaria alternata on Rehmannia glutinosa in China

Plant Disease ◽  
2020 ◽  
Vol 104 (11) ◽  
pp. 3059-3059
Author(s):  
Jia-fang Du ◽  
Wen-kai Nian ◽  
Zhang-jin Zhou ◽  
Tao Dou ◽  
Guo-hong Song ◽  
...  
Keyword(s):  
Alternaria Alternata ◽  
Leaf Spot ◽  
Leaf Spot Disease ◽  
Rehmannia Glutinosa ◽  
Spot Disease

scholarly journals Distribution and Characterization of AKT Homologs in the Tangerine Pathotype of Alternaria alternata

2000 ◽  
Vol 90 (7) ◽  
pp. 762-768 ◽  
Author(s):  
A. Masunaka ◽  
A. Tanaka ◽  
T. Tsuge ◽  
T. L. Peever ◽  
L. W. Timmer ◽  
...  
Keyword(s):  
Alternaria Alternata ◽  
Sequence Similarity ◽  
Structural Similarity ◽  
Toxin Production ◽  
Brown Spot ◽  
Japanese Pear ◽  
Black Rot ◽  
Acid Moiety ◽  
High Sequence Similarity ◽  
Rough Lemon

The tangerine pathotype of Alternaria alternata produces a host-selective toxin (HST), known as ACT-toxin, and causes Alternaria brown spot disease of citrus. The structure of ACT-toxin is closely related to AK- and AF-toxins, which are HSTs produced by the Japanese pear and strawberry pathotypes of A. alternata, respectively. AC-, AK-, and AF-toxins are chemically similar and share a 9,10-epoxy-8-hydroxy-9-methyl-decatrienoic acid moiety. Two genes controlling AK-toxin biosynthesis (AKT1 and AKT2) were recently cloned from the Japanese pear pathotype of A. alternata. Portions of these genes were used as heterologous probes in Southern blots, that detected homologs in 13 isolates of A. alternata tangerine pathotype from Minneola tangelo in Florida. Partial sequencing of the homologs in one of these isolates demonstrated high sequence similarity to AKT1 (89.8%) and to AKT2 (90.7%). AKT homologs were not detected in nine isolates of A. alternata from rough lemon, six isolates of nonpathogenic A. alternata, and one isolate of A. citri that causes citrus black rot. The presence of homologs in the Minneola isolates and not in the rough lemon isolates, nonpathogens or black rot isolates, correlates perfectly to pathogenicity on Iyo tangerine and ACT-toxin production. Functionality of the homologs was demonstrated by detection of transcripts using reverse transcription-polymerase chain reaction (RT-PCR) in total RNA of the tangerine pathotype of A. alternata. The high sequence similarity of AKT and AKT homologs in the tangerine patho-type, combined with the structural similarity of AK-toxin and ACT-toxin, may indicate that these homologs are involved in the biosynthesis of the decatrienoic acid moiety of ACT-toxin.

Effects of Culture Media, Exposure Time and Temperature on Near-Ultraviolet-Induced Sporulation of Alternaria alternata

1985 ◽  
Vol 48 (4) ◽  
pp. 316-319
Author(s):  
CHENG-I WEI ◽  
DIANE D. SWARTZ ◽  
JOHN A. CORNELL
Keyword(s):  
Exposure Time ◽  
Alternaria Alternata ◽  
Culture Medium ◽  
Culture Media ◽  
Media Exposure ◽  
Potato Dextrose Agar ◽  
Uv Exposure ◽  
Strain Atcc ◽  
Ultraviolet Exposure ◽  
Near Ultraviolet

Effects of culture media, near-ultraviolet exposure time, and temperature on sporulation of Alternaria alternata were investigated. Strains RL 671-2 and ATCC 36068 were cultivated on Potato Dextrose Agar (PDA), V8 Juice Agar (V8 Agar) and Mycological Agar (MA). The best culture medium for sporulation of strain RL 671-2 was PDA, followed by V8 agar, with only negligible numbers of spores appearing on MA. Near-UV exposure significantly increased sporulation in strain RL 671-2 on PDA and V8 agar. Significantly higher (P&lt;0.01) spore counts were found in PDA cultures of this strain exposed to near-UV at 35 than at 20°C. On V8 agar significantly more spores were observed at 20 than at 35°C. MA was not a satisfactory medium for sporulation of ATCC 36068. Both PDA and V8 agar equally supported sporulation for this strain (ATCC 36068) at all exposure times.

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